1. Field of the Invention
The present invention relates to a vibration actuator, and more particularly, to a vibration actuator using a piezoelectric element.
2. Description of the Related Art
Recently, as personal digital assistants having large liquid crystal display (LCD) screens provided for user convenience have been released onto the market, a touch screen scheme has been adopted therein, and a vibration motor for generating vibrations at the time of a touch has been used therewith.
A vibration motor, a component converting electrical energy into mechanical vibrations using the principle of generating electromagnetic force, is mounted in a personal digital assistant to thereby be used for silently notifying a user of call reception by transferring vibrations thereto.
According to the related art, a brush type structure using a commutator or a scheme of periodically generating electromagnetic force according to a resonant frequency to generate vibrations has been used.
However, in the brush type structure using the commutator, since a brush passes through a clearance between segments of the commutator at the time of motor rotation, mechanical friction and electrical sparks may be caused and foreign objects may be generated, such that a lifespan of a motor may be reduced. In addition, since a certain amount of time is required to arrive at a target vibration amount due to rotational inertia at the time of the application of voltage to the motor, there are limitations in implementing vibrations appropriate for a touch screen.
In addition, in the case of a linear vibrator, contact between components vibrating in an internal space and noise therefrom may be generated, such that performance and characteristics of the vibrator are changed, effecting the performance of a portable electronic device using the linear vibrator.
Therefore, research into a vibration actuator that may be slimmed in accordance with the market trend for miniaturization and slimness in portable electronic devices, may be efficiently produced, and does not have a negative effect on performance and characteristics of a vibrator even in the case in which several factors act has been undertaken.
The following Related Art Document (Patent Document) discloses a vibration generator generating vibrations using a piezoelectric element.